Labels:bird | earth | identikit | paper | pen and ink | person | poster | skep | sky | tree | water | windowpane OCR: Ethmoid sinus Frontal sinus Nasal Maxillary passage sinus Sinuses are air r-filled cavities in the face that connect the nasal passages (The sphenoidal sinuses are not shown because they are located behind the ethmoid sinuses.) Ethmold